Compressor control device



May 24, 1938. B 5, A|KMAN v 2,118,130

COMPRESSOR vCONTROL DEVICE Filed July 16, 1957 2 Sheets-Sheet l 2 4Q iQ l @5 @6 m EURTDN 5. AIKMAN ATTORNEY May 24, 1938. B. s. AIKMAN' COMPRESSOR CONTROL DEVICE Filed July 16, 1957 2 Sheets-Sheet 2 ELIRTDN 5. AIKMAN ATTORNEY Patented May 24, 1938 UNITED STATES mrsnr orFIcE COMPRESSOR CONTROL DEVICE Application July 16, 1937, Serial No. 153,895

22 Claims.

governor for controlling a compressor in accordance with different ranges. of pressure variation in a receiving reservoir.

The noise of operation of a fluid compressor carried on a vehicle in street railway or subway l service, although usually not noticeable while the vehicle is in motion, becomes annoying. and undesirable when the vehicle is brought to a stop, and in order to avoid this condition, controlmeans have heretofore been proposedfor preventing the l compressor from operating while a vehicle is standing still, or unless the main reservoir pressure has been reduced to a very low degree. The control means referred to have generally necessitated considerable alteration in the design of the V compressor governor apparatus, thus involving expense.

One object of my invention is to provide improved automatic means for preventing a vehicle carried compressor from operating while the ve- A.25 hicle is at a standstill, unless the reservoir pressure is reduced to a very low degree, which means is embodied in a mechanism of simple and inexpensive design.

Another object of my invention is to provide vso automatic means of the above type which .is

1,0 brake apparatus, which means is responsive to operation of the brakes for causing the governor to start and stop the compressor in accordance with variations in fluid pressure in the reservoir within a certain range at one time, and within 45 a different range at another time.

Other objects and advanatages will appear in the following description of the invention, taken with reference to the accompanying drawings, in which:

Fig- 1 is a diagrammatic view, partly in section, of a uid compressing apparatus embodying my invention, and having associated therewith a simplified lform of fluid pressure brake;

Fig. 2 is a diagrammatic sectional view of a 55 compressor control device similar to that shown in Fig. 1 but embodying my invention in a different form;

Figs. 3 and 4 are diagrammatic sectional views illustrating further modifications of the compressor control device; and :i5

Figs. 5 and 6 are fragmentary sectional views Yof compressor governors embodying still other forms of my invention.

The apparatus shown in Fig. 1 of the drawings comprises a fluid compressor I, a reservoir 2 for 10 receiving fluid compressed thereby, a compressor governor 3 for controlling the supply of current to the compressor driving motor, an auxiliary control device 4, and fluid pressure braking means comprising a brake cylinder 5 and a brake valve 51.5 device E. The compressor governor 3 is preferably of the well known pressure range type such as that `disclosed in the Patent 1,615,365 issued to Clyde C. Farmer on January 25, 1927, and is adapted to close the compressor motor circuit 20 in response to a predetermined minimum iluid pressure and to break the circuit in response to a predetermined maximum fluid pressure. In Fig. 1 the governor 3 is illustrated diagrammatically, as comprising a flexible diaphragm 9'sub- 25 ject to the pressure of iiuid in a chamber I0 and adapted to operate a switch mechanism, not shown, through the medium of a switch operating member II which is urged downwardly toward a circuit closing position by a pair of springs I 2. When the pressure of fluid in the chamber Illis below a predetermined value the springs I2 are adapted to maintain the governor 3 in circuit closing position for eiecting supply of current to the electric driving motor of the compressor and upon a predetermined increase in the pressure of uid in the chamber It the diaphragm 9 is adapted to be operated to move the switch mechanism of the governor into another position for cutting off the supply of current to the corni0 presser driving motor.

rihe brake Vvalve device '6 may be of any well known type adapted when moved to release position to establish communication from the brake cylinder 5 by way of a pipe I4 to the atmosphere .-4,5 and when moved to a brake application position to supply fluid under pressure from the reservoir 2 through a pipe I5 and the pipe I4 to the brake cylinder for eiecting an application of the brakes.

According to the invention the auxiliary con- 50 trol ldevice 4 comprises a main casing section I6 and a cover section I'I containing a pressure reducing mechanism including a flexible diaphragm I8, which is clamped between said sections and has on the lower side thereof a chamg5 ber I9 and on the upper side a chamber 20, the chamber 20 being connected through a passage and pipe 2I with the reservoir 2. Fitted within a central opening in the diaphragm I8 is a valve seat member 23, which is secured to the diaphragm by means of a screw-threaded nut 24 and has one portion in sliding engagement within a bore formedrby an annular shoulder 25 provided in the cover section I 'I and another portion in sliding engagement within an apertured sleeve portion 26 of the main casing I6. A valve 28 is carried within the seat member 23 and is adapted to be urged into engagement with a seat 29, formed on said member, by the pressure of a spring 38 thatis interposed between the valve and the cover section I1. The valve 28 has a iluted stem 32 extending through a suitable bore in the seat member 23, the stem having on the lower end thereof a valve 33 which is adapted for engagement with a seat 34 formed on Vthe casing section I6 for controlling communication between the chamber I 9 and an atmospheric exhaust passage 35. A coil spring 36 is interposed between the lower wall of the chamber I9 and the seat member 23 for biasing the seat'member and the diaphragm I8 upwardly.

Operativelyjaligned with the lower end of the valve 33 is a plunger element 38, which has a valve portion 4I aligned for seating engagement with/a seat 39 formed on the casing section I6.

YThe element 38 is slidably mounted in a suitable bore in the casingsection I and extends into a chamber 42, which-is open to the atmosphere by way of a port 43, the valve portion 4I being normally held away from the seat 39 by the weight of the plunger 38. Clamped between-the casing section I6 and a cover plate 45 is a flexible diaphragm 44, which is subject to the pressure of fluid in a chamber 46 communicating through a branch pipe I4a with therbrake cylinder 5, the diaphragm being operative on an increase in fluid pressure in said chamber for moving the element 38 upwardly.

When the compressor I is operated to supply fluid under pressure to the reservoirY 2, fluid under pressure flows therefrom through theVY pipe and passage 2I to the chamber 20 within the auxiliary control device 4 and acts against the diaphragm I8 so as to force the diaphragm andthe seat member 23 downwardly, With the valve 33 held in engagement with the seat 34 due to the pressure of the spring 30, downward movement of the seat member 23 causes the seat 29 to move' away from the valve 28, and fluid under pressure isthensupplied from the chamber 29 past the fluted stem 32 and through the apertures in the sleeve portion 26 to the chamber I9 and thence through Va pipe 49 to the chamber II] in the compressorV governor 3. Y

The supply of fluid under pressure from the reservoir 2 by way of the chamber 20 in the auxiliary control device to the chamber I9 therein andV thence to the chamber I9 in the compressor governor 3 will continue until the combined forces of fluid under pressure in the chamber I9 acting against the diaphragm I8 and of the spring 36 acting against the seat member 23 become slightly greater than the pressure of fluid in the chamber 29 acting on the diaphragm, at which time the diaphragm will be operated to move the seat member upwardly until the seat 29 engages the valve 28. Y It will thus be apparent that the pressure reducing mechanism in the auxiliary control device 4 is operative to maintain the pressure of Vout of operation when said reservoir pressure exceeds 70 pounds, and assuming alsothat a force of pounds is required to compress the spring 33 in the auxiliary control device, the compressor Y governor 3 should then be adjusted to close the circuit to the compressor driving motor when the fluid pressure in the chamber I0 falls below 50. pounds and to respond to anY increase in fluid pressure in said chamber to approximately 60 pounds for breaking the circuit to the driving motor. Consequently, while the auxiliary control device 4 is in the normal position shown in Fig.

1 of the drawings, said device and the compressor governor 3 are cooperative to control operation of the compressor I for maintaining the fluid pressure within the rreservoir 2 within a 60 to 70 pound range. u Y, Y f

It will be understood that if thepressure of fluid in the reservoir 2 should for any reason be reduced below the combined pressures of the spring 39 and of the uid under pressure'in chamber I 9, the pressures of thefluid in the chamber I9 and of theA spring 36'will then move the diaphragm I8 and the seat member 23 upwardly togetherV with the valve 28 so as to unseat the valve 33, thereby venting uidunder pressure to a degree below the minimum pressure forVv which the governor 3 is adjusted, the governor will then startY the compressor.

If the brake valve devicer is now operated to effect the supply of fluid under pressure from the reservoir 2 to the brake cylinder 5 for causing an application of the brakes and .for thereby bringing the vehicle to a stop, fluid under pressure is at the same time supplied by way Yof the branch pipe I4a to the chamber 46 in the auxiliary control device 4 and operates the 'dia'- phragm 44 Vto move the plunger element 38 andY Y the valve portion 4I into engagement with the seat 39. As the element 38 is thus moved upwardly, the upper end thereof engages the pro,- jection on the end of the valve 33 and shifts the valves 33 Yand 28 to their uppermost positions .against the pressure of the spring 39, thevalve 28 being then positioned'beyond the range of movement of the seat member 23, upward movement of which is checked on engagement of the ring 24 with the annular shoulder 25.

With the valve 28 in the Yauxiliary control device 4 thus maintained unseated, fluid at the pressure of that in the reservoir 2 is then supplied to the chamber I8 in the governor device 3, and since the governor device is adjusted toY control operation of the compressor I in response yto variations in pressure in the chamber Il) within a range a predetermined degree less than the range of pressures normally maintained in the reservoir 2, the compressor I will be cut out of operation while the vehicle is at a standstill. It will be understood, of course, that in case the pressure of huid in the reservoir 2 is reduced below the minimum pressure for which the governor 3 is adjusted, the compressor will be cut into operation to 'supply suiiicient fluid under pressure to the reservoir to restore the fluid pressure therein to the predetermined value below the normal pressure, but under usual operating conditions it is to be expected that when the vehicle is stopped the fluid pressure in the reservoir will remain high enough to prevent operation of the compressor.

When the brakes are released in order to permit the vehicle to proceed, iiuid under pressure is vented from the brake cylinder- 5 and the connected chamber 46 in the usual manner, and the operative elements in the auxiliary control device 4 again assume the position shown in Fig. 1 for supplying fluid at reduced pressure to the governor device 3 and thereby effecting operation of the compressor to build up the fluid pressure in the reservoir 2 to that normally carried.

According to the modified form of my invention illustrated in Fig. 2 of the drawings, there is provided an auxiliary control device 55, the principle of operation of which is similar to that of the control device 4 shown in Fig. l, and which includes, in addition, means for delaying the supply of fluid at brake cylinder pressure to the control device for a predetermined interval after an application of the brakes has been eiiected, so as to avoid undesired stopping of the compressor when the brakes are applied only for reducing the speed of the vehicle. The upper portion of the auxiliary control device 50 containing the pressure reducing mechanism is not shown in detail in Fig. 2 of the drawings asv the structural features thereof are substantially the same as those of the corresponding portion of the device 4 shown in Fig. l, it being noted that the diaphragm 44 in the mechanism shown in Fig. 2 is adapted to operate the valve 33 through the medium of a plunger element 38a, which is somewhat different from the element 38 shown in Fig. l in that the element 33a is provided with a gasket 52 adapted for seating engagement with an annular portion 53 of the casing surrounding the bore in which said element is mounted. A spring 54 is provided for biasing the element 38a and the diaphragm 34 shown in Fig. 2 toward a normal position.

The auxiliary control device 50 is provided with a timing portion comprising a casing section 55 having slidably mounted therein a timing piston 56, which is subject on one side to the pressure o1 uid in a volume chamber 5l and on the other side to the pressure of uid in a chamber 58 connected through a passage 59 in the casing with the branch pipe Ida leading to the brake cylinder. The piston 55 has a restricted port 65 through which fluid under pressure may ow at a slow rate from one of the chambers 58 and 5i to the other. A valve 62 is contained in a valve Vchamber 63 formed in the casing section 55 for controlling communication from the chamber 553 through the valve chamber to the chamber 45a at the lower side of the diaphragm 54. The valve 62 has a luted stem 54, the lower end of which operatively engages the timing piston 55, which is urged upwardly by the force of spring E7 disposed in the chamber 5l, so that the valve 62 is normally maintained unseated as shown 'in Fig. 2 of the drawings. A spring 68 is interposed between the valve 62 and the upper wall of the chamber 53 for urging the valve downwardly toward seated position.

While the fluid pressure brakes are released, the volume chamber 57 and the chamber 58 are connected to the atmosphere by way of the passage 59 and the brake cylinder pipe Ma, and the spring 6l is thus permitted to act through the medium of the piston 56 and the Valve stem 64 to maintain the valve 52 unseated so that the `diaphragm chamber lla is also connected to the atmosphere through the valve chamber 63 and the other communications already mentioned. With the plunger element 38a maintained in the position shown in the drawings by the force of the spring 54, the pressure reducing mechanism in the auxiliary control device 5B is operative to supply Iluid under pressure through the pipe 49 to the compressor governor at a pressure a predetermined degree less than that of the fluid supplied through the pipe 2| from the reservoir, as already explained in connection with the apparatus shown in Fig. l.

lli/'hen an application of the brakes is eiected, uid at the pressure of that in the brake cylinder is supplied through the pipe Ma and the passage 59 to the piston chamber 58 at a faster rate than that of iiow of fluid from the chamber 58 through the restricted port 65 in the timing piston 56, which is thereby moved downwardly against the pressure of the spring 6i' and into en gagement with a stop member lil provided on the casing within the chamber 5l. As the piston 56 thus moves downwardly, the spring 68 becomes effective to move the valve 62 into seated position so as to cut off communication between the chamber 58 and the valve chamber 63. Mean'- while, fluid under pressure continues to flow from the chamber 58 through the restricted port 6l) to the volume chamber 57, and after apredetermined interval the iiuid pressure in the chamber 5i acting on the piston 56 as aided by the spring E? becomes sumcient to move the piston upwardly into engagement with the valve stem 65, the valve 62 being then unseated.

With the valve 52 unseated, fluid at brake cylinder pressure is supplied through the chamber 53 to the diaphragm chamber 42a and acts on the diaphragm fill to effect operation of the auxiliary control device 5D to permit uid to now from the reservoir to the compressor governoi` without reduction in pressure. As a result, the compressor on the vehicle is not operated while the vehicle is standing, unless the reservoir pressure should fall to the low degree at which the compressor governor is adjusted to operate as hereinbefore explained.

Referring to Fig. 3 of the drawings, the invention is shown in another form comprising an auxiliary control device i2 which is associated with means for preventing the device from functioning to cause the compressor governor to cut the compressor out of operation before the vehicle is brought to a stop by an application of the brakes. The auxiliary control device 72 comprises pressure reducing valve means, which although not shown in detail in Fig. 3, will be understood to be similar to that shown in the device 5 in Fig. l. of the drawings, and in addition the control device 'l2 is provided with a portion 73 containing valve means controlling the supyply of iiuid at brake cylinder pressure to a dia,-

phragm chamber 46h` at the lower side of the diaphragm 44. Mounted in the portion 13 is a timing piston 15 having on one side a chamber 16 communicating with the brake cylinder pipe |4a and on the other side a volume chamber 11, which communicates through a restricted port 18 formed inV the piston 15 with the chamber 16. A spring 80 is disposed in the chamber 11 for urging the piston 15 upwardly and into engagement with the stem 8| of a valve 82 contained in a valve chamber 83, the valve being thereby normally maintained in unseated position for permitting communication between the chamber 16 and valve chamber 83. A spring 84 is provided for urging the valve 82 toward seated position.

Thefvalve chamber 83 is adapted to communicate through a passage 86 with a valve chamber 81, which is open through a passage 88 to the diaphragm 4617 and which contains a valve 89 operatively aligned with `a valve seat 90 and adapted to control communication from the passage 86 to the chamber 81. The valve 89 is normally held unseated by the force of gravity and as shown in Fig. 3 is adapted to engage the upper end of a sealing element 9| having a stem 92 slidably mounted in Ya suitable bore in the casing and extending outwardly thereof.

The valve 89 is adapted to be operated through the medium of the stem 92 by a vehicle retardation responsive device, which comprises an inertia controlled element 94 having oppositely extending lugs 95 and 96 and a centrally depending weight portion 91, the 4lugs' 95 and 96 being supported on pins 99 and |00, respectively, which are carried by trunnion portions 99d and |00a of the casing. The arrangement of the member 94 is suchV that thelugs 95 and 96 are'in line with the path of movement of the vehicle, so that when the speed of the vehicle is reduced, the inertia of the weight portion 91 causes the member 94 to tilt about one of thev pins 99 and |00, depending upon the direction of movement of the vehicle, thereby bringing the portion of the Vmember between the lugs into operative engagement with the stem 92, which is thus moved upwardly to effect engagement of the valve 89 with the seat 90.

Assuming that the auxiliary control device 12 is associated with a vehicle braking and fluid compressor apparatus such as that shown inV Fig. l of the drawings, if while the vehicle is in motion an application of the rbrakes is effected, fluid under pressure is supplied from the usual brake cylinder through the pipe |4a to the chamber 16 and forces the piston 15 downwardly against the pressure Yof the spring 80 to permit the spring 84 to seat the valve 82 for temporarily cutting off communication from the chamber 16 to the chamber 83. When the pressure of fluid in the chamber 11 has been built up to a predetermined value by flow of fluid through the port 18 in the piston, the spring 80 becomes effective to move the piston 15 upwardly, again unseating the valve 82 and allowing fluid under pressure to flow from the chamber 16V to the chamber 83 and the passage 86. So long as the rate of deceleration of the vehicle exceeds a predetermined degree, however, the memberV 94 is effective to maintain the valve 89 seated, in the manner already'explained, and since fluid under pressure is thus prevented from owing into the chamber 81 and the connected diaphragm chamber 46h, theauxiliary control device 12 continues to function to permit the usual operation of the. compressor.

If the application of the brakes is sulcient to bring the vehicle to a stop, the inertia controlled member 94 again assumes the normal position shown in Fig. 3, thereby permitting the valve 89 to move downwardly from the seat 90. With the valve 89 unseated, fluid at brake cylinder pressure is supplied from the passage 86 through the chamber 81 to the diaphragm chamber 46h and operates the diaphragm 44 to render the. reducing valve mechanism ineiective as hereinbefore described, with the result that operation of the compressor is prevented unless the iiuid pressure in the reservoir should fallV below the minimum value for which the compressor governor is adjusted.

Referring to Fig. 4 of the drawings, a modied form of my invention is shown comprising an auxiliary control device |04, which includes the features of the auxiliary control device 4 shown in Fig. 1, including the diaphragm 44, and is further provided with means for preventing supply of fluid under pressure from the vehicle brake cylinder for operating the diaphragm 44 until the vehicle doors have been opened.

'Ihe diaphragm 44, which operates the plunger element 38 as already explained, is subject to the pressure of fluid in a diaphragm chamber 46c formed in a casing section |05, and is normally urged by a vspring |06 into seating engagement with a seat rib |01 for controlling com- Y munication from the brake cylinder pipe |4a chamber 46c into operative engagement with the e diaphragm 44, which in the normal position thereof holds the valve ||0 unseated against the biasing force of a spring ||2 that is interposed between the valve and the lower wall of the chamber,|09. The valve chamber 09 communicates by way of a passage ||4 with a door en- Ying back flow of fluid from the chamber |09 Yto the pipe ||5.

In operation, when the brake cylinder on the vehicle is supplied with fluid under pressure for effecting application of the brakes, the brake cylinder pipe |4a becomes charged with Huid under pressure as already explained. With the diaphragm 44 in seating engagement with the seat rib |01, however, fluid at the pressure of that of the brake cylinder is prevented from flowing into the chamber 46c, so that the auxiliary control device |04 continues to cooperate with the usual compressor governor to permit the compressor to mfaintain the reservoir charged at the normal operating pressure. After the vehicle has been brought to a stop for taking on or discharging passengers, fluid under pressure is supplied in the usual manner through the pipe I5 for operating the door engine ||6 to open the door, and at the same time fluid under pressure is supplied fromV the pipe i I5 through the passage I4, past theI check valve H1, through the valve chamber |09.

and past the unseated valve |2 to the diaphragm chamber 46c. The diaphragm 44 is thereby moved upwardly to establish communication from the passage |08 to the chamber46c, at thesame time permitting the spring i2 to move the valve with the chamber |28.

into seated` position. Fluid under pressure is then supplied from the brake cylinder by way of the pipe Ma and passage |08 to the diaphragm chamfber 45C, so that the auxiliary control device |04 is conditioned to permit operation of the compressoil governor to cut the compressor out of action while the vehicle is standing.

In Fig. 5 of the drawings, my invention is shown embodied in a unitary compressor governor device which comprises a governor portion ||8 and an auxiliary control portion I9 which may be secured to the governor portion by any suitable means such as bolts, not shown. The governor portion ||84 is of a usual construction and is not shown in detail, it being understood that this portion comprises a switch mechanism', not shown, which is adapted to be operated through the medium of a switch operating member I I9 by a flexiblediaphragm subject to the opposing pressures of spring |21 and of iluid in a chamber |22 which is connected by way of a pipe |23 with the reservoir receiving fluid compressed by the compressor. When the pressure of iiuid in the chamber |22 is below a predetermined value the spring |2| adaptedl to maintain the member I I9 and the associated switch mechanism in circuit closing position for effecting supply of power to the driving motor of the compressor, and upon a predetermined increase in the pressure of fluid in the chamber |22, the diaphragm |20 is adapted to be operated to move the switch mechanism into anotherposition for cutting oi further supply of power to the driving motor.

The auxiliary control portion I I9 comprises a booster piston |25 slidably mounted in a bushing |26, the piston being subject on one side to the pressure of fluid in the chamber |22 and on the other side to the forcey of a spring |21 which is disposed in a chamber |28 formed in the portion The piston |25 is adapted normally to be forced downwardly into sealing engagement with a gasket |30 by the iiuid pressure in the chamber |22', but when the fluid pressures in the chambers |22 and |28 are equalized in the manner herein- L after explained, the spring |21 is adapted to act through the medium of the piston |25 and a follower member |3| in engagement therewith to apply a force against the diaphragm |20 in addition to the pressure of :duid in the chamber |22.

vCommunication between the chamber |22 and the chamber |28 is controlled Vby a valve |33 which is contained in a valve chamber |34 connected through a passage |35 with the chamber |22 and by way of a bore |31 and a passage |38 A spring is provided in the valve chamber |44 for normally maintaining the valve |33 in seated position, as shown in the drawings.

The valve |33 has a fluted stem |4| slidably mounted in the bore |31, which stem operatively engages a similar fiuted stem |42 that terminates in a valve portion |43. The valve portion |43 is disposed in a chamber |44 which is open to the atmosphere through a passage |45, and is adapted to be moved into seating engagement with a seat |41 by operation of a ilexible diaphragm |48 which is adapted to be subjected to iiuid at brake cylinder pressure supplied to a chamber |49 through the brake cylinder pipe |4a.

' In operation, with the brakes released and the chamber |49 consequently at atmospheric pressure, the spring |40 is effective to maintain the valve |33 seated and the valve |43 unseated, so that the chamber |28 beneath the booster piston |`25-is connected to the atmosphere through the passage |38, the bore |31, and the vented'chamber |44. Fluid under pressure supplied from the reservo-ir by way of the pipe |23 to the chamber |22 is thus effective to maintain the booster piston |25 in its lowermost position as shown in the drawings, and at the same time the 'fluid in the chamber I 22 acts through the medium of the diaphragm |25 to eff-ect operation of the governor portion ||8 in the usual manner for controlling operation of the compressor.

It should be understood that the governor portion I I8 shown in Fig. 5 is adjusted to respond to variations in pressure within Athe normal range ci pressures at which the reservoir is to be maintained charged, so that with the brakes released and the governor diaphragm |20 subject only to the pressure of uid supplied from the reservoir, as just described, the compressor is permitted to operate to supply iiuid to the reservoir at full operating pressure.

When an application of the brakes is effected, iluid under pressure supplied from the brake cylinder by way of the pipe |4a to the chamber |49 operates the diaphragm |48 to seat the valve portion |43 while unseating the valve |33. With the valve |33 unseated, fluid under pressure' is`- permitted to ow from the diaphragm chamber |22 through the passage |35, the chamber |34, the bore |31 and passage |38 to the chamber |28, thereby equalizing the fluid pressures on opposite sides of the booster piston |25, so that the springV |21 becomes effective to apply additional force against the diaphragm |20 through the medium of the piston and the follower member |3| will be apparent that by reason of the additional force applied to the diaphragm |20 by the spring |21, the governor portion ||8 will be rendered eiective to cut the compressorv out of action-While the vehicle is at a standstill, unless the reservoir pressure in the chamber 22 should fall a predetermined degree lower than the normal minimum pressure for which the governor is adjusted.

As shown in Fig. 6 of the drawings, the invention may be embodied in a structure that is somewhat similar to that shown in Fig. 5, except that an auxiliary control Vportion |59 is substituted for the portion ||9 shown in Fig. 5. The auxiliary control portion |50 comprises a booster piston |5| having on one side a chamber |52 .connected with the atmosphere through an opening |53, and subject on its lower side to the pressure of uid in a chamber |54 which communicates through a passage |55 with the brake cylinder pipe |4a. The piston I5! is provided with a stem |51 slidably mounted in a suitable bore in the casing, which stem extends into the chamber |22 and terminates in a head portion |58 in operative alignment with the diaphragm |20. An annular gasket |60 is inserted .in the lower face of the head portion |58 and is adapted for sealing engagementv with an annular seat |6| formed on the lower wall of the chamber |22, and a similarl gasket |62 is inserted in the upper portion of the piston IBI for sealing against an annular portion |63 of the casing surrounding the bore in whichl the stem |51 is mounted. For minimizing leakage oi fluid from the chamber |54 to the chamber |52 an annular packing |65 is secured to the piston |5|` by means of a clamping ring |66.

Whilev the brakes of the vehicle are released,

the chamber |54 below the booster piston |5| is` connected to the atmosphere by way of the brake cylinder |40l and the pressure of uid at reservoir pressure in the chamber 22 acting on the head portion |58, as aided by the Weight of the ItY tive to maintain said element in the normal position shown in Fig. 6 of the drawings, the gasket |60 being in sealing engagement with the annular rib |6I. The diaphragm |20 of the governor portion is accordingly subject only to the pressure of fluid in the chamber |22, so that the compressor is permitted to operate in the usual manner to maintain the reservoir charged with fluid at full operating pressure. If the vehiclebrakes are applied, however, iiuid under pressure is supplied from the brake cylinder through the pipe |4a andthe passage |55 to the chamber |54, and acts through the medium of the piston |5i and the head portion |58 to apply additional force to the diaphragm |20, thereby causing the vgovernor to prevent normal operation of the compressor While the vehicle is not in motion.

While several illustrative embodiments of the invention have been described in detail, it is not my intention to limit its scope to those embodiments or otherwise than by the terms of the appended claims.

Having now described my inventionywhat I claim as new and desire to secure by Letters Patent, is:

1. In combination, a motor driven compressor, a reservoir intowhich fluid compressed by said compressor is supplied, regulatory means operative by variations in iiuid pressure for causing said compressor to start and stop when the pressure in the reservoir reaches given minimum and maximum pressures, respectively, control Vmeans operated by variations in fluid pressure for causing said regulatory means to effect the starting and stopping of the compressor when the pressure in the reservoir reaches minimum and maximum pressures different from said given pressures, and braking means including a brake cylinder communicating with said control means, whereby the fluid pressure on said control means is varied in accordance with operation of the braking means.

2. In combination, a compressor, means for Vdriving the compressor, a reservoir into which Y and at another time supplying fluid to said governor at a lower pressure than that insaid reservoir, uid pressure responsive means for controlling said auxiliary valve means, and means for supplying and releasing fluid under pressure to and fro-m said fluid pressure responsive means.

3. The combination with an electric motor driven compressor, a reservoir for receiving uid compressed thereby, and a compressor governor for controlling the opening and closing of the compressor motor circuit in accordance with variations in fluid pressure within a certain zone, of a control device normally effective to supply fluid from the reservoir tosaid governor at a pressure a predetermined degree less than the pressure prevailing in said reservoir, said control device being adapted to be actuated for supplying fluid at full reservoir pressure to said governor, uid pressure braking apparatus including a normally vented chamber, means operative to supply fluid under pressure to said chamber in effecting an application of the brakes, and means subject to the pressure of fluid in said chamber and operative upon a predetermined increase therein to actuate said control device for supplying iluid at full reservoir pressure to said governor.

4. The combination with a vehicle carried compressor, an electric driving motor therefor, and .governor means including a movable abutment responsive to the pressure of fluid compressed by' the compressor for controlling the circuit to said 5. The combination with a vehicle braking apparatus including a brake cylinder, a compressor, a reservoir into which fluid compressed by said compressor is supplied, and a governor adjusted to operate at a predetermined maximum degree oi uid pressure in said reservoir for cutting the compressor out of action and at a predetermined minimum degree of reservoir pressure for cutting the compressor into action, of control means normally. effective for causing the governor to cut the compressor into and out of action when the minimum and maximum pressures of fluid in the reservoir are higher than said predetermined pressures for which the governor is adjusted, meansV responsive to an increase in fluid pressure for rendering said control means ineffective to control said governor, and an always open communication connecting said fluid pressure operated means to said brake cylinder.

6. The combination with a Vehicle braking apparatus including a brake cylinder, a compressor, a reservoir into which fluid compressed by said compressor is supplied, and a governor adjusted to operate ata predetermined maximum degree of iluid pressure in said reservoir for cutting the compressor out of action and at a predetermined minimum degree of reservoir pressure for cut- Y ting the compressor into action, of control means normally effective for causing the governor to cut the compressor into and out of action when the minimum and maximum pressures of fluid in the reservoir are higher than said predetermined pressures for which the governor is adjusted, means responsive to an increase in fluid pressure for rendering said control means ineffective to control said governor, and mechanism controlling communication between said brake cylinder and said fluid pressure responsive means, said mechanism Consisting of a normally open valve and means operative on an increase in fluid pressure in said brake cylinder for temporarily closing said valve.

'7. The combination with a vehicle braking apparatus including .a brake cylinder, a compressor, a reservoir into which iiuid compressed by said compressor is supplied, and a governor adjusted to operate at a predetermined maximum degree of fluid pressure in said reservoir for cutting the compressor out of action and at a predetermined minimum degree of reservoir pressure for cutting the compressor into action, of control means normally operative for causing the governor to cut the compressor into and out of action when the minimum and maximum pressures of fluid in the reservoir are higher than said predetermined pressures for which the governor is adjusted, means responsive to an increase in fluid pressure aliarse for rendering said control means ineffective to control said governor, a normally open valve controlling communication between said brake cylinder and said fluid pressure responsive means, and inertia controlled means responsive to retardation of the vehicle for closing said valve.

8. The combination with a vehicle braking apparatus including a brake cylinder, a compressor, a reservoir into which fluid compressed by said compressor is supplied, and a governor adjusted to operate at a predetermined maximum degree of fluid pressure in said reservoir for cutting the compressor out of action and at a predetermined minimum degree of reservoir pressure for cutting the compressor into action, of control means normally operative for causing the governor to cut the compressor into and out of action when the minimum and maximum pressures of fluid in the reservoir are higher than said predetermined pressures for which the governor is* adjusted, means responsive to an increase in fluid pressure for rendering said control means ineffective to control said governor, a door engine operative by iluid under pressure, and means operative by fluid supplied to said door engine for controlling communication from said brake cylinder to said fluid pressure responsive means.

9. The combination with a vehicle carried fluid compressor, an electric driving motor therefor, and governor means including a movable abutment responsive to the pressure of fluid compressed by the compressor for controlling the circuit to said motor, of fluid pressure brake apparatus including va normally vented chamber, means for supplying fluid under pressure to said chamber in effecting an application of the brakes, and auxiliary control means comprising a spring and means operative upon a predetermined increase in the pressure of fluid in said chamber for effecting application of the force of said spring to said movable abutment to augment the pressure thereon of iluid supplied by the compressor.

10. The combination with a vehicle carried fluid compressor, an electric driving motor therefor, and governor means including a movable abutment responsive to the pressure of fluid compressed by the compressor for controlling the circuit to said motor, of fluid pressure braking apparatus including a normally vented chamber and means for supplying iluid under pressure to said chamber in effecting an application of the brakes, and means for applying additional force to said movable'abutment in the governor comprising a piston subject to the pressure of fluid in said chamber.

11. In combination, a fluid compressor, a reservoir into which fluid is compressed by said compressor, a compressor governor operated by variations in iluid pressure in Ya chamber for controlling the operation of the compressor, a valve device for controlling the fluid pressure in said chamber comprising a spring, a movable abutment subject on one side to the pressure oi said spring and the fluid pressure in said chamber and on the opposite side to the pressure of fluid compressed by the compressor into said reservoir, a valve operated upon an increase in reservoir pressure on said abutment for supplying fluid under pressure to said chamber, and a valve operated upon a reduction in reservoir pressure on said abutment for venting fluid under pressure from said chamber.

12. In combination, a fluid compressor, a reservoir into which fluid is compressed by said compressor, a compressor governor operated by variations in fluid pressure in a chamber for controlling the operation of the compressor, a valve device for controlling the fluid pressure in said chamber comprising a spring, a movable abutment subject on one side to the pressure of said spring and the fluid pressure in said chamber and on the opposite side to the pressure of fluid compressed by the compresso-r into said reservoir, a Valve operated upon an increase in reservoir pressure on said abutment for supplying fluid under pressure to said chamber, a valve operated upon a reduction in reservoir pressure on said abutment for venting fluid under pressure from said chamber, and additional means operated by fluid under pressure for opening said supply valve.

13. In combination, a fluid compressor, a reservoir into which fluid is compressed by said compressor, a compressor governor operated by variations in fluid pressure in a chamber for controlling the operation of the compressor, a valve device for controlling the fluid pressure in said chamber comprising a spring, a movable abutment subject on one side to the pressure of said spring and the yfluid pressure in said chamber and on the opposite side to the pressure of fluid compressed by the compressor into said reservoir, a valve operated upon an increase in reservoir pressure on said abutment for supplying fluid under pressure to said chamber, a valve operated upon a reduction in reservoir pressure on said abutment for venting fluid under pressure from said chamber, and additional means operated by fluid under pressure for opening said supply valve and for closing communication through which said vent valve vents fluid from said chamber.

lll. The combination with a vehicle braking equipment, a fluid compressor, a reservoir into which fluid compressed by the compressor is supplied, driving means for said compressor, and a fluid pressure responsive governor operative at a predetermined minimum degree of fluid pressure to start said driving means and at a predetermined maximum degree of fluid pressure to stop said driving means, of fluid pressure controlled means subject to the pressure of fluid compressed by the compressor for controlling the supply of fluid under pressure to said governor and normally operative to limit the maximum degree of pressure of fluid supplied to said governor to a degree less than the pressure 'of fluid compressed by the compressor, and means operative byan increase in fluid pressure in effecting an application of the brakes to effect'the supply of fluid at the same pressure as that in said reservoir to said governor.

15. In combination, a fluid compressor, a reservoir into Which iluid compressed by said compressor is supplied, regulatory means operative to effect the starting and stopping of the compressor when subjected to predetermined minimum and maximum pressures, respectively, a fluid pressure operated control device operative to control the pressure to which said regulatory means is subjected, Said control device having a normal position wherein said regulatory means is subjected to pressure bearing one ratio to the fluid pressure in said reservoir, said control device being movable to another position on an increase in iluid pressure for subjecting said regulatory means to pressure bearing a different ratio to said reservoir pressure, and means for varying the iluid pressure on said control device.

16. In combination with a vehicle brake equipment, a fluid compressor, a reservoir into which fluid compressed by said compressor is supplied, regulatory means operative to effect the starting and stopping of the compressor when subjected to predetermined minimum and maximum pressures, respectively, a fluid pressure operated control device adapted to control the pressure to which said regulatory means is subjected, said control device having a normal position wherein said regulatory means is subjected to pressure bearing one ratio to the fluid pressure in said reservoir, said control device being movable to another position on an increase in fluid pressure for subjecting said regulatory means to pressure bearing a different ratio to said reservoir pressure, and means operative upon application of the brakes for varying the fluid pressure on said control device. Y

17. In combination, a fluid compressor, a reservoir into which fluid compressed by'said compressor is supplied, a single compressor governor adapted to start and stop the compressor when subjected to predetermined minimum and maximum pressures, respectively, a fluid pressure operated control device adapted to control the pressure to which said governor is subjected, said control device having a normal position wherein said governor is subjected to pressure bearing one ratio to the fluid pressure in said reservoir, said control device being movable to another position upon an increase in fluid pressure for subjecting said governor to pressure bearing a different ratio to said reservoir pressure, and means for varying the fluid pressure on said control device. f

18. In combination, a fluid compressor, a reservoir for receiving fluid compressed thereby, a compressor governor operated by variations in fluid pressure for effecting the starting and stopping of the compressor, and a control valve device comprising a casing having a reservoir chamber communicating with said reservoir and a governor chamber Vcommunicating with said governor, a movable abutment interposed between said chambers and carrying a Valve seat, a movable Valve element normally positioned to be engageable by said seat for controlling communication from the one chamber to the other, a spring biasing said abutment toward said valve element in opposition to the pressure of fluid in said governor chamber, and means operative for at times positioning said valve element beyond the range of movement of the valve seat on said abutment. Y e Y 19. In combination, a fluid compressor, a reservoir for receiving fluid compressed thereby, a compressor governor operated by variations in fluid pressure for effecting the starting and stopping of the compressor', and a control valve device comprising a casing having a reservoir chamber communicating with said reservoir and a governor chamber communicatingwith said governor, a movable abutment interposed between said chambers and carrying a valve seat, a valve element normally engageable by the seat on said abutment for controlling communication from the one chamber to the other and also from said governor chamber to the atmosphere, a spring acting on said abutment to oppose the pressure ofV fluid in said reservoir chamber, and means operative at times to prevent engagement of said valve seat with said valve element.

20. In combination, a fluid compressor, a reservoir for receiving fluid compressed thereby, a compressor governor operated by variations in fluid pressure for effecting the starting and stopping of the compressor, and a control valve device comprising a casing having a reservoir chamber communicating with said reservoir and a governor chamber communicating with said governor, a movable abutment interposed between said chambers and carrying a valve seat, a valve element normally engageable by the seat on said labutment for controlling communication from Y the one chamber to the other and also from said governor chamber to the atmosphere, a spring acting on said abutment to oppose the pressure of fluid in said reservoir chamber, and means opera.- tive to condition said valveelement to prevent engagement thereof by said valve seat While preventing escape of fluid under pressure from theY governor chamber to the atmosphere.

21, In combination, a fluid compressor, a reservoir for receiving fluid compressed thereby, a compressor governor operated by Yvariations in fluid pressure for effecting -the starting and stoping of the compressor, and a control valve device comprising a casing having a reservoir chamber communicating with said reservoir and a governor chamber communicating with said governor, a movable abutment interposed between 'said chambers and carrying a valve seat, a valve element normally engageable by the seat on said abutment for controlling communication from the one chamber to the other and also from said governor chamber to the atmosphere, a spring acting on said abutment to oppose the pressure of fluid in said reservoir chamber, and means automatically operative when the vehicle is stopped to seal said governor chamber from the atmosphere and to prevent engagement of said seat with said Valve element for cutting off communication between said reservoir and governor chambers.

22. In combination with a vehicle carried fluid compressorya reservoir for receiving fluid compressed thereby, and a compressor governor operated according to variations in fluid pressure for effecting the starting and stopping of the compressor, an auxiliary control device comprising valve means operativeto control the supply of fluid under pressure from said reservoir to said governor, a spring, a movable abutment subject on one side to the pressure of fluid in said reservoir and on the opposite side to the pressures of said spring and of the fluid in said governor, said abutment being adapted normally to control seating and unseating of said valve means, and means automatically rendered effective when the vehicle is stopped to actuate said valve means independently of the abutment for permitting uninterrupted supply of fluid under pressure from said reservoir to said governor.

BURTON S. AIKMAN. 

